1. Field of the Invention
The present invention relates to a touch device, especially to an electronic paper touch device, which is capable of utilizing an electronic paper structure to perform a capacitive touch detection procedure.
2. Description of the Related Art
Please refer to FIG. 1a-1c, which illustrate the operation principle of a prior art electronic paper display. In FIG. 1a, a positive voltage +VEink is applied to top ends of all electronic paper display cells to make all of the electronic paper display cells display a white color. In FIG. 1b, a negative voltage −VEink is applied to the top end of a specific electronic paper display cell to attract black particles and expel white particles to make the specific electronic paper display cell display a black color. In FIG. 1c, the specific electronic paper display cell still displays the black color after the negative voltage −VEink is removed. To make the specific electronic paper display cell change to display the white color, the positive voltage +VEink has to be applied to the top end of the specific electronic paper display cell to attract the white particles and expel the black particles. In driving the electronic paper display cell to make it change display colors, a sufficiently large voltage (that is, VEink must be larger than a threshold) and a sufficiently long driving time are necessary. If the applied voltage is not large enough or the driving time is not long enough, the electronic paper display cell will not change display colors, that is, the electronic paper display cell has a bi-stable characteristic.
By taking advantage of the bi-stable characteristic of the electronic paper display cell, the present invention proposes an electronic paper touch device.